Belgium pair Romelu Lukaku and Eden Hazard will miss the Nations League third-placed play-off with Italy because of “muscle overloads”.
Chelsea striker Lukaku will go back to Belgium, rather than London, first from Italy and boss Roberto Martinez does not know when he will be fit.
Lukaku played all of Thursday’s 3-2 semi-final defeat by France and scored.
“They’re not in best conditions to play,” said Martinez of Lukaku and Real Madrid’s Eden Hazard.
“They’re leaving the national team camp due to these problems – I don’t know how long it will take for them to recover.”
He said there was no issue from Chelsea with Lukaku going to Belgium rather than heading straight back to his club side.
“Obviously there is an excellent understanding between the two sets of medical staff and we want to do the best for the player,” he added.
“Every decision is also made in agreement with the club.”
Chelsea visit Brentford next Saturday.